Ground ivy (creeping Charlie)

Ground ivy (Glechoma hederacea), commonly called creeping Charlie or gill-over-the-ground, is a low, creeping perennial broadleaf in the mint family. It has round to kidney-shaped leaves with scalloped (round-toothed) margins, arranged opposite one another on long petioles attached to square stems that root at the nodes as they creep, forming dense mats. In spring it produces small funnel-shaped blue to lavender flowers in clusters in the leaf axils. The square stems, opposite scalloped leaves, mat-forming creeping habit, and a minty odor when crushed distinguish ground ivy from look-alikes such as common mallow and henbit; the rooting-at-nodes habit aids its rapid spread.

Ground ivy degrades the stand by forming dense, ground-hugging mats of creeping stems that smother and crowd out turfgrass, leaving thin or bare turf especially in shaded, moist areas where the grass is already struggling. The mats spread rapidly by rooting stolons, steadily enlarging and displacing desirable grass, and the patchy blue-flowering colonies disrupt lawn uniformity. Because it persists through winter and regenerates from stolon fragments, infestations are difficult to clear and tend to recur.

Ground ivy is a creeping perennial that spreads primarily by stolons (above-ground runners) that root at the nodes, and it can also reproduce by seed. The rooting stolons let it form expanding mats and regenerate readily from fragments, which is why incomplete hand-pulling often makes infestations worse. It is essentially evergreen in many climates, persisting through winter, and flowers in spring; its mint-family vigor and nodal rooting make it a tenacious perennial that returns from any stolon segments left in the soil.

Ground ivy thrives in shaded, moist, fertile sites and is a classic indicator of damp, low-light conditions, readily invading lawns under tree canopies, along north-facing areas, and in poorly drained or overwatered turf. It also tolerates sun but is most aggressive where turf is thinned by shade and moisture, and it spreads quickly by stolons to crowd out weakened grass. Disturbed, shaded, and chronically moist areas are the most prone to invasion, and reducing shade and excess moisture limits its advance.